一、环境描述

Oracle 12c 单实例DataGuard

Rhel 7.3

二、测试过程

主库操作

1.关闭DG,切换日志

SQL> alter system set log_archive_dest_state_2=defer;

System altered.

SQL> show parameter log_archive_dest_state_2

NAME                                 TYPE        VALUE

------------------------------------ ----------- ------------------------------

log_archive_dest_state_2             string      DEFER

log_archive_dest_state_20            string      enable

log_archive_dest_state_21            string      enable

log_archive_dest_state_22            string      enable

log_archive_dest_state_23            string      enable

log_archive_dest_state_24            string      enable

log_archive_dest_state_25            string      enable

log_archive_dest_state_26            string      enable

log_archive_dest_state_27            string      enable

log_archive_dest_state_28            string      enable

log_archive_dest_state_29            string      enable

SQL> alter system switch logfile;

System altered.

SQL> alter system switch logfile;

System altered.

SQL> 

2.rman删除归档

RMAN> list archivelog all;

List of Archived Log Copies for database with db_unique_name ORCL

=====================================================================

Key     Thrd Seq     S Low Time            

------- ---- ------- - --------------------

40      1    31      A 26-NOV-2017 19:15:13

        Name: /oracle/arch/1_31_958415134.dbf

42      1    32      A 26-NOV-2017 19:22:34

        Name: /oracle/arch/1_32_958415134.dbf

RMAN> delete noprompt archivelog all;

released channel: ORA_DISK_1

allocated channel: ORA_DISK_1

channel ORA_DISK_1: SID=39 device type=DISK

RMAN-08137: WARNING: archived log not deleted, needed for standby or upstream capture process

archived log file name=/oracle/arch/1_32_958415134.dbf thread=1 sequence=32

List of Archived Log Copies for database with db_unique_name ORCL

=====================================================================

Key     Thrd Seq     S Low Time            

------- ---- ------- - --------------------

40      1    31      A 26-NOV-2017 19:15:13

        Name: /oracle/arch/1_31_958415134.dbf

deleted archived log

archived log file name=/oracle/arch/1_31_958415134.dbf RECID=40 STAMP=961096954

Deleted 1 objects

RMAN> 

三、小结

当我们DG环境，人为或者异常情况导致DG异常，没有被应用的归档日志是不会被删除的。这里可能会出现一个问题就是

当我们的磁盘空间紧张，可能生成大量的日志占满磁盘，导致数据库无法写入的问题。需要我们有监控系统，发现DG异常及时处理

，千万不要等着影响业务才被动的去处理。